Numerous balancing devices comprising a balance board and a roller are available on the market. For example, U.S. Pat. No. 6,019,712 discloses a platform which tilts upon a hemisphere attached to the underside thereof. The platform also has a grooved tract along its periphery wherein is placed a movable ball. A consumer can amuse himself while tilting upon the platform and causing the ball to move along the track. U.S. Pat. No. 5,152,691 discloses a roller having a slot in the center thereof and tapered end sections. A board having a guide rail attached to its horizontal center line is in the slot and moves within a limited range relative to the roller. U.S. Pat. No. 5,190,506 discloses a deck and a roller assembly comprising two wheels mounted on a common axle. A cable maintains a contact between the deck and the roller assembly and limits the longitudinal displacement of the deck relative to the roller assembly. U.S. Pat. No. 4,911,440 discloses a roller, a board normally resting on the roller, and a releasable connector interconnecting the board and the roller. The connector maintains the roller perpendicular to the longitudinal axis of the board, thereby limiting the longitudinal movement of the board relative to the roller. U.S. Pat. No. 4,826,159 discloses a cylindrical roller having a coarse surface and a balance board having a pair of tracts and stops so as to limit the movement of the board relative to the roller. U.S. Pat. No. 4,601,469 discloses a balance board having a foot platform and a roller retained in a frame underneath the platform by a pin extending through the roller and into guide channels formed underside of the frame. U.S. Pat. No. 4,191,371 discloses a spherical fulcrum and a board having a flat top for foot support and a pair of stop means attached to the underside of the board so as to limit the extent of movement of the spherical fulcrum with respect to the platform. U.S. Pat. No. 3,895,794 discloses a balance board and a cylindrical roller which is confined within a cavity formed near a center portion of the board. U.S. Pat. No. 3,389,910 discloses a cylindrical base and a board having a tally scale on the side of the board. The consumers can compare, using the tally scale, the length of the board they can shift relative to the longitudinal center line of the roller.
In sum, prior art balancing devices limit the movement of the board relative to the roller. What is needed is a balancing device providing complete freedom of movement of the board relative to the roller.